Relevance. Despite successful use of cardiac resynchronization therapy (CRT) in patients with systolic CHF, there are still issues concerning establishment of accurate indications of its use, including based on QRS width, morphology, and LVEF. Objective. Assess role of QRS extension and / or its morphologic changes on prognosis of CHF patients. Materials and methods. For assessment of the factors influencing prognosis, follow-up data of 277 consistent patients with CHF FC II–IV, treated in the HF department of A. L. Miasnikov Institute of Clinical Cardiology, was analysed concerning HF decompensation in 2002–2006. Prognosis was known in 239 (86.5 %) patients, average follow-up period was 8 years. Results. Single-factor analysis revealed that CHF FC >II, high SHOKS score (CHF severity scale), low LVEF, QRS extension, a bundle-branch block, low systolic BP, and myocardium scar, predicted mortality. However, multivariate Cox’s analysis showed only low systolic BP or high SHOCK score to be independent predictors of lethal outcome. The additional multivariate analysis which included CHF severity (NYHA FC or SHOCK score), LVEF and QRS duration or morphology – presence of bundle-branch block (as parameters considered accounted for at establishment of CRT indications) – all three parameters appeared to be independent factors influencing mortality. For more accurate analysis, patients were divided to 4 groups by LVEF value and QRS duration: QRS >104 ms, LVEF <35 %; QRS >104 ms, LVEF >35 %; QRS <104 ms, LVEF <35 %; QRS <104 ms, LVEF >35 %. Only group with poor LVEF and wide QRS had significantly worst CHF prognosis as compared to other three groups. Conclusion. Only combination of low LVEF and QRS extension, but not an individual indicator, allows defining a group of patients with the highest risk of death.

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